1. Field of the Invention
The present invention relates to a commutator type rotary electric machine and more specifically to its brush holder.
2. Related Arts
Japanese Utility Model Application Laid-Open No. 58-28556 proposes to integrate by resin a brush holder of a surface commutator type electric rotating machine with an end bracket which is a structural member retaining an armature shaft.
However, although the surface commutator type electric rotary machine according to the above publication presents an advantage in the reduction of number of component parts and simplification of structure, there are problems such as the deteriorated strength of end bracket and brush holder and the deformation of bearing retaining section because heat cannot be radiated effectively from brush due to the fact that the brush as a heat generating source is surrounded by a resin mold which has a very poor capacity of heat transfer, and as a result temperature tends to rise excessively around the brush.